Automatic diverter for pneumatic conveyers



y 7, 1953 R. J. CHILDRESS AUTOMATIC DIVERTER FOR PNEUMATIC CONVEYERSFiled May 22, 1950 2 Sheets-Sheet l INVENTOR E RANDALL J. CHILDRESSATTORNEY July 7, 1953 R. J. CHIILDRESS 2,644, 22 AUTOMATIC DIVERTER FORPNEUMATIC CONVEYERS Filed May 22; 1950 2 sheets-she s; 2

FIG. 4 FIG; 5 v

l INVfNTOR 10 1 9 I RANDALL J. CHILDRESS BY 7%A'C). W

A TTORNE Y Patented July 7, 1953 OFFICE AUTQMATIC 'nIvERTER FortNEUMATIC CONVEYERSC" v I Randafl J. Childress, Norwalk Calif assignor toGeneral Mills, Inc., a corporation of Delaware This invention relates topneumatic conveyers, and moreparticularly to an improved automatic valveor diverter for such a conveyer.

Pneumatic conveyers are well known in which material is fed into asuitable suction leg or tube and is transported through the tube by theflow of air therethro'ugh. One problem in'such conveyers involves theintroduction of the material to be conveyed. 1 If this material is fedbygravity from a supply hopper or other chute, it sometimes happens thatthe rate of supply of material isso great that the suction-- leg becomesclogged; The supply chute is then choked in turn, and the work requiredto clear the lines is both timeconsuming'and expensivem L w a v a It isaccordingly one object of the 'present'invention to provide improvedmeans fordiverting the stock at the supply inlet ofa pneumatic conveyer,when the conveyer becomes choked.

A further object is the provisio'n of an automatic valve or diverter incombinationwith an "air inlet, at the junction between the materialsupply chute and the main conveyer leg. 21-. v

Another object isthe provision of an automatic diverter ior a pneumaticconveyer, which will automatically divert the supply of material awayfrom the conveyer when the latter becomes choked.

- Other objects and advantages of-the invention will beapparentfrom thefollowing specification in which a preferred. embodiment of theinvention is described. 4

In theldrawings forming a. part of this application, and in which likereference. characters indicate like parts, I l

Figure 1.is a side elevation,- partly in section, showing constructionof the materialsupply chute and air intake in a priorart pneumaticIconveyer.- a

. Fig. .2 is a similar view illustrating a manual means for diversion ofthe stock.

. Fig. 3 is a view on the line 33 of Fig. 2 looking down the mainconveyer tube through the air inlet. 1 1

Fig.4 is a partial sectional-view with certain portions broken away,-showing. the .device of Figs. 1 and 2,mod'ifie'd according to thepresent invention. I r

3 Fig. 5 is a View similar to- Fig. 4,but illustrating the choking-ofthe main conveyer leg.

main conveyer leg-while "the choked condition is relieved.

. Fig. 6 15a similar viewillustratingthe manner- Application May 22,msas i l No. 163,554 12 Claims. (01.302 32) Fig.1- is an enlargedpartial side View showing details of the mounting of the diverter plateand the manner of its adjustment. i

Fig; 8' is a plan View of a blank from which a diverterplate can beformed, and

Fig. 9 is-a partial sectional viewon 99'*of Fig; 7.

As shown in Figs. l

the line and 2, a typical prior art pneumatic system includes a mainsuction' leg or conveyer tube I0, which is illustrated as substantiallyhorizontal, but may also be'inclined. A suction fan (not shown) isconnected at the remote end of this suction leg in order to -draw airthrough theconveyer tube l0 and to convey the desired material by meansof such air flow. 1 The material to'be fed to the conveyer tube H] isfedfrom a supply hopper I2 through an inlet chute l4having asubstantially rectangular cross section. An intermediate section 16provides for a change in cross section from the rectangular sectionofthe chute I4 to the ultimate circular section of the conveyer tube I0. Between this intermediate section 16. and the conveyer tube- 10 is anadjustable auxiliary air inlet device ISof known construction.

In the present case, the supply'hopper I2 is indicated as communicatingdirectly with aroll stand '20 for milling wheat or other grain intoflour. The machine 20 includes rolls 22 between which the material isuniformly fed from a supply hopper or distributor 24. The stock which isformed by the rolls 22 then enters the supplyhopper l2 and supply-chuteI4 and is fedto the main conveyer leg l0.

. The material inlet chute [4, which is ofrectangular ,cross section,has a lower or rear wall 26 which is inclined from the supply chutetoward the main conveyer tube and which servesas a means for guiding andsupportingth-e material as it is fed downwardly by gravity to theconve-ver leg l0. I Y

- In this. lower wall26 an airinlet opening 30' is provided. Asindicated in Figsl and 3, the air inlet opening 30 is substantiallyrectangular in plan and is defined by upper and lower edges 28 and -32,respectively, and parallel sides 3i. and 33. A- rectangular frameworkhaving outwardly projecting flanges 34 surrounds and defines theopening. This frame 34 is inclined along the plane of'the lower Wall 26of the inlet supply chute I4 and includes a depending extension '36 atits lower end on which hinges 38 are located. These hinges 38support asimilar flange 40 of a corresponding framework 42 at one end of an airintake chute 0r bell 44. This air' intake section, which is sometimesreferred to as a cascade section, has an outwardly flared end 46 throughwhich air enters the cascade 44 to be fed through opening 30 and alongthe conveyer tube 10.

The material dropped from the rolls 22 and passing downwardly throughthe hopper l2 and supply chute l4'will thus be entrained in the aircurrents rushing in toward the main conveyer tube Ill.

It should be noted that, in this installation, the, conveyer tube Indraws air from three sources. The first source is the air inlet or'cascad'ejfl. The second is the supply chute l4, and the third is theadjustable circumferentiahauxiliary air i-nlet I8, the details of whichhave-been omitted.

since they form no part of the presentinvention. A gasket 48 may becarried by the frame member 42 of the air inlet valve 44 in order toforman air tight seal betweeii the frame members 34 and 42; These. framemembers; which are. hinged Q the ro11stand-2l Ordinarily, the devicewill be operated in. the positionof Fig. 1. During such operation,however, it sometimes happens that the main conveyer tube I becomes:partially or fully choked. In such a situation, iftherolls 22 areoperating on stock continuously received at that point, the

stock fedirom the rolls willagradually back up through the intermediatesections l6, supply chute I4, and: hopper 122' and-may evlen choke. thesystem all the way upztothe rolls: 22.

It has: therefore been necessary to have anoperator watch the operationof? the conveyer leg relatively closely and pull the ring 587170 releasethe clamp whenever the choked condition threatened to clog the roll-istand.

When the clamp 50 is pulled ih'SllCh an emergency, the inlet valve 5'4is permitted to swing downwardly to the position ofFig. 2'. Theframework34', and the opening defined thereby,-1ie directly beneath the supplychute portion M". Therefore any material which is choked? this chute candrop directly by gravity to the lower floor as shownby the pile ofmaterial 62 on fi'oor 64' in Fig. 2.

As soon as the choked condition within con-v veyer tube [0 is relieved,a process which in the past" has consumed considerabletime and efiort;then the air inlet can be restored to the" position of-Fig. 1 andthe'clamp'Ellrepl'aced, whileriormaloperation is then resumed.

Since the equilibrium condition in a pneinnatie conveyer of this type israther critical, andsince the flow of stock from the roll stand may varyfrom: time to time, there haveb'een frequntsituations in. which theconvey'er tube l0. has-become partially or fully choked and necessitatedthe: release of: clamp 5M0 dump material on the floor. It will" beunderstood that as long as the conveyor leg I0 is substantially chokedso that very little air can rush in through the intakegopening- 30,. theonly place for the material coming from the supply chute M to go isdirectly downwardly to the lower floor. I p 7 According to the presentinvention, as illustrated in Figs. 4-9, the air inlet bell or cascadeE4; can be removed and an automatic divert'er plate, indicated generallyat 66, can be installed 4 in the opening 30. The construction of thdiverter plate 66 is best shown in Figs. 8 and 9. Fig. 8 illustrates aflat blank'of sheet metal cut to provide the necessary elements for thediverter or valve plate 66. In the present case, since the opening 30 issubstantially rectangular, the plate member 65:? is aISWreCtangIilan Theplate blank is cut withmaralll sides 68 and") which are spaced just farenough apart to substantially fill the width of the opening 30 betweensides 3| and 33.. p

The plate" also has upper and lower edges 12 and "M, respectively, whichare spaced apart a distancesomevtihafi less than the length of opening tfl betwen its top and bottom edges 28 and 32. The upper edge 12 of thediverter plate 66 corresponds shape to the top edge 28 of the opening,-which in this case is perpendicular to the parallel side walls 6r edges.

At each sideof; the: plate; 66 bearing extensions are: provided;-Thusea-bearing extension IGi-s-provided at edge 68;;whilegabearing:member, 80 proiects at; side H1. The bearing portions 15 and; 80 areprovided: with openings Hi and: 82'. As shownj the; remaining figures,-the bearing portions; 16 and- 81} are bent downwardly at: right angles,viewed: from: the, top in: Fig; 8, while the ends 12 and; T4 ofnlatearei curved upward? slightiy. Thus the plate and: its: bearingextensions.- will havethe; general configuration shown in the sideelevation in -Figs: 4, 5; and 6. plate; can accordingly be; mounted inthe- Dlane of the opening Bil-, with; the upperand lower edges of theplate Hand: 14 inclined: somewhat: inwardly toward the; inneryportion ofthe chute as viewed; Fige 41,;- and with: the bearin portions: 16 and!projecting outwardlyfor en.- gagement with: a'suita-ble; supportingshartz' The supportingshaft: 1M1,- as-iiiustrated inf-Fig 9 ,;passesthrough the-openings is and 82 in' the bearing members 16' amt and-hasits'ends return bent, around the projecting edges or' flanges or theframe members: 3.4-.- as* shown at lit-and: 88'. The clamping engagementof irmrtions-v 8&- and 88" is suificienhto hold the" shaft; 84- anddi'vlerter plate- 6& in; the desired position within: the plane. ofopening 30, while at the same time the specific: locationa of. the?shaft-s M;- can be: adjusted by" slidins?- the'porticns' and 88upanddown'the frame member to l'ocatesth'ei pivotala axis" ofpla'te 66'at any desired point in the opening 30:

As shown in Figs; ls-G the'diizerter pIate BB' ispositionedirr-the-uppen portion: of the opening an. In other words, thelocation of: supporting shaft 84: adiustect so that: the? upper edge 12of the diverted plate, 66 will engage against the .uppe'r edge: 280i:the frame: 3'4: defining the? opening and will thus limit clockwiserotation of the plateias' viewed: inzFigz, 4'. Because? the plate 6:6 isshorter from top to bottom; than: the vertical length of theopening an,therewiilsiie aisubstantially open area at thelower: portion of theopening through which air can enter the pneumatic system. asshown by thearrow 92. As already pointed out,

some additional air is drawn into the system:

throughthe supply chutei' H? mm the roll stand 20, as indicated byarrows 90.

' It will be clear from: Figi 8 that: the" bearing portions 16 and 80.of: the diizerter plate- 66 are" located: within, the upperhalfor theplate; In

other words, these Portions are located; some.- where between one-thirdand one-half the distance from the top towardthe bottom of the, plate.

During normal operation of the pneumatic 5 system, as illustrated inFig. 4, the air rushing in through the lower portion ofv the air intakeopening 30 as indicated by arrow 92 will tend to hold the diverter plate66 in the position of the figure. Thus the stock which is guideddownwardly by gravity through the chute [4 in the direction of arrows 99will be further guided and supported by the diverter plate 66 so thatthe material is directed toward the main conveyor tube Ill and is pickedup by the additional air stream indicated at 92. As long as the conveyertube I is clear and as long as the normal flow of air is maintained, thepartswill remain in this relative position and all material comingthrough the supply chute M will be carried in the usual state ofsuspension by the flow of air involved.

If, however, the material is fed too rapidly through the supply chutel4, a choked condition may be obtained within the conveyer tube ID. Apartially choked condition is illustrated at 94 in Fig. 5. As indicatedhere, the material piles up at 94 in the lower portion of the conveyertube and intermediate sectionand thus tends to block the main air inletopening between the lower edge 14 of diverter plate 66 and the loweredge 32 of opening 36.

As soon as the fiow of air at this point is blocked so that the suctionat opening 30 is decreased, there will be a tendency for the lower end14 of plate 66 to drop so that the plate is more nearly vertical. Thelocation of the hearing portions 16 and 86 above the midpoint of plate66 makes the lower portion of said plate heavier so that it will tend toswing from the position of Fig. 5 toward the position of Fig. 6.

The tendencyof plate 66 to swing from the position of Fig. 5 to that ofFig. 6 as soon as a partial choke occurs is also increased because ofthe tendency of the system to try to draw air in through opening 30 atthe upper edge 12 of the plate as shown by arrow 96 in Fig. 5. When thelower portion of the conveyer tube I6 becomes blocked there is a greatertendency to draw the remaining flow of necessary air through the upperportions of opening 30 and this tendency also helps rock the plate-66 tothe diverting position of Fig. 6, 1 1

As soon as the plate 66 begins to swing in this manner, the upper edge12 of the plate will project inwardly within the supply chute l4 andwill extend across the path of the material being fed through the chute.The plate 66 will accordingly divert the material away from the mainconveyer tube 10 as indicated by the arrow 98. At the same time some ofthe material which has piled up as indicated at 94 in Fig. 5 will bepermitted to drop out of the lower portion of the opening 36 at thepoint indicated by the arrow I60 in Fig. 6.

In some cases, this diverting action is improved if the supporting shaft84 is moved downwardly as indicated for example by the dotted lineposition of Fig. 7, so that there will be a space or opening between theupper edge 12 of the plate and the upper edge 28 of the opening 36. Thuspart of the normal supply of air required by the pneumatic conveyerwould be received through opening 30 both above and below the plate. Asthe lower portion of the conveyer tube becomes choked, the differentialpressure on the plate, particularly at its upper portion, will tend torotate the plate to the diverting position. Thus an important feature ofthe present invention is the provision of means for vertical adjustmentof the location of the pivotal'axis of the plate between the upper andloweredges of. opening 30.

In the operation of the device according to the present invention, thereis the very. definite advantage that the diverter plate 66 can be soadjusted that it will function automatically to move from the positionof Fig. 4 to theposition of Fig. 6 as soon as a partial choke occurs. Aslong as the choke is only partial, there will'still be an unchoked areain the upper portionof the main conveyer tube I0 through which air .canflow. The air flowing through this area can itself pick up the extramaterial and clean the tube II] to relieve the choked condition. There.fore the present invention furnishes means of diverting the stock fromthe supply chute the moment a partial choke occurs and thus giving thesystem an opportunity to clear itself out Without complete clogging ofthe main conveyer or supply chute or roll stand. It is then onlynecessary to manually tilt the diverter plate 66 backfrom the positionof Fig. 6 to theposition'of Fig. 4 as soon as the observer notes thatthe choked condition has been relieved.

A construction has accordingly been provided which accomplishes theobjects set forth at the beginning of this specification. I

Since minor variations and changes in the exact details ofconstruction'will be apparent to persons skilled in this field, it isintended that this invention shall cover all such changes andmodifications as fall within the spirit and scope of the appendedclaims.

Now, therefore, I claim: r

1. An automatic diverter for a pneumatic conveyer having a suction legand a hopper above the leg for supplying material downwardly by gravityflow to the leg, comprising an inclined wall guiding and supporting thematerial-be-' tween the hopper and leg, said wall having an air inletopening therein, a valve plate, and means pivotally mounting theplate'in said opening for rotation on an axis lying in the plane of thewall and extending transversely thereof, between an operating positionin which the plate lies in the plane of the wall and guides the materialto the leg, and a dumping position in which it intercepts the materialfrom the hopper and diverts it away from the suction leg, the relativearea, weight and location of the plate and the relative location of itspivotal axis requiring automatic movement of the plate from operating todumping position in response to substantial reduction in the volume rateof flow through the suction leg.

2. An automatic diverter according to claim 1 in which the valve plate,in its operating position, covers only the upper portion of the inletopening.

3. An automatic diverter according to claim 1 in which the mountingmeans for the valve plate is adjustable along the wall in a directionperpendicular to said axis to vary the position of the late within theopening.

4. An automatic diverter according to claim 1 in which the valve plateis rectangular and includes portions extending above and below theshaft.

5. An automatic diverter for a pneumatic conveyor having a suction legextending in one direction and a supply chute extending downwardlytoward the suction leg and intersecting the suction leg at an angle,which comprises a downwardly inclined lower wall portion on the chute atthe point of intersection with the suction leg,

7 said iwall having an air intake iopening therein, and adiventing platemounted in the .opening for pivotal :movement on .an axis :lying in theplane of the .opening and. extending transversely across the .opening at.a point spaced substantially from both the upper and lower edges of theopening, the plate having upper and lower portions extending :above andbelow the axis, with the upper portion "having the-size and shape .01that (part lot the opening above the axis and the :lower portion havingla size and shape smaller than that part of the .opening below the axis,the relative area, weight .and location of the plate and the relativelocation of its ipivotal axis requiring automatic movement of the plate.from operating o d mpi s position inresponse to substantial reductionthe volume r te of flow through he suction leg.

.5. aut matic diyertenior a pneumatieeo veyer havin a suct on leextendin in one direction an ,a simply ch t extendin d wnw rd toward thesuct on e an intersectin th suct on le t an n e, which ompr se a d wnwly l ned s owe W31 po ion on th chute at the po nt o inte secti n withthe suction le aid w ll ha in a r int ke op nin t e and a v in platemounte th open oripiro almevement on. n. s lying in the pl n o he one mi-s nd extend n tran e sel acro s he open n at a o nt sp ced ubstantia lyom both the up r an lower e ges of the ene ina the p ate halt n up er anlo e or o s e tending above and below the axis, with the upper portionhaving the size an shape of that part of the opening above the axis andthe lower portion having a size and shape smaller tha that part of theopening below the axis, and with the upper portion of the diverter platebeing smaller than the lower portion and with said axis located withinthe upper half of said opening.

-'7. An automatic diverter for a penumatic eonveyer having a horizontalsuction leg and a downwardly inclined supply chute intersecting thesuction leg for feeding material thereto, which comprises an inclinedbottom wall in the chute, said wall having a rectangular opening thereinwith top and bottom edges extending perpendicularly across the wall, arectangular diverting plate having substantially the same width as theopening, but shorter than the opening, and means mounting the plate inthe opening for pivotal movement around an axis lying in the plane ofthe opening and parallel to said top edge but spaced substantially belowit, the plate being movable from an operating position in which it "liesin the plane of the opening and closes the upper portion thereof to adiverting position in which an upper portion of the plate extendsinwardly of the chute in the path of the material to divert the materialaway from the suction leg, the relative area weight and location of theplate and the relative location of its pivotal axis requiring automaticmovement of the plate from op- 8 crating. toidmnping position :inresponse to .sub-

reduction the -.volume rate of how throughmhesuction leg.

.18. A ioombination ;material supply and air :inlet val-ye e'foriapneumatic conveyor having a suction leg, of. enclosed section withopposed upper and lower avalahportionswhich comprises a material supplyrchuite having ialowier wall inclined .downwardlymo the loot-tom wall.of :the Suction conveying leg, .s'aid rwall hayingianair :inlet openingdefined ;by upper and lower edges with the lower edge on iarlevelsubstantially lloelow the top :wall portion o.t the snot-ion leg, and ;a.diverter plate pivoted in saidtopening :ior rotation on a transverseaxis located at an intermediate portion of both :the (opening andpl ate,the relative area, weight and location of the plate and the relativelocation of its l-pirvotail' taxis requiring automatic mouementiof itheplate from operating to dumpinc position response to substantialreduction in the volume rate of how through the suction leg I V 19,. A.pneumatic conveyer according to claim ;8 in which the lower edge or the:air inlet opening is at suhtsantially :the same level as the bottomwall portion of thesuction leg.

10. A pneumatic conveyer according to claim 8 in which the ,diverterplate :has ,a width .Slibstanially t e sameias e opening and is shorterthan i the opening.

1 1. Aipneumatic conveyer according to claim :8 in whichthe .axisof thediverter plate pivot is located above the centerof the opening.

12- Aoomhination material supplyand air inlet valve tor La :p1-1eumaticconveyer having a suction leg of enclosed section with opposed upper andlower wall portions, which comprises a material supplychute having alower :wall inclined downwardiy to the bottom wall of the suctionconvey-- ing -leg, said wail-having an air inlet opening defined byupper and lower edges with the lower edge on a level substantially:below the top wall portion of the sucti n l and a eliverter platepivoted said .openingqfor rotation on a transverse axis iocated at anintermediate portion of both. the opening and plate, the axis of saiddiverter'plate :pivot beinglocatesl above the c n er of the opening andals o located above the center of the plate.

RANDALL .J CHILDRESS.

Reference Cited i he file of this patent UNITED STATES PATENTS

